The guiding catheter is used in conjunction with coronary medical procedures, radiological medical procedures and neurological medical procedures. The guiding catheter provides a channel or tube for the further positioning of, for example, an angioplasty balloon catheter. The guiding catheter is initially positioned with the use of a guide wire. The balloon catheter or guide wire is introduced into the lumen of the guiding catheter and, for coronary catheterization, is advanced from the arterial entrance site of the patient to the ostium or septum of the potentially obstructed coronary artery. The ostium is the mouth-like opening in a body organ which, in coronary catheterization, is the heart of the patient. The guiding catheter supports the angioplasty balloon catheter as it is moved into the coronary artery and across the target lesion. Additionally, the guiding catheter allows monitoring of the aortic or coronary ostial pressure as well as visualization of the vascular system proximate thereto with the use of contrast media injections and electronic monitorization of the resulting radioactive emissions.
The guiding catheter forms a significant part of a more complex angioplasty system. This angioplasty system may include further devices for diagnostic purposes as well as interventional purposes. An ideal guiding catheter design may include the following elements:
A. The catheter should advance through the vascular system smoothly and responsively and permit precise maneuvering by the physician. The catheter should exhibit axial rigidity and responsiveness to torque forces applied by the physician at the proximal end of the catheter.
B. The catheter, and particularly the catheter tip, should be able to be positioned in the desired coronary ostium in a stable manner and without causing mural trauma or ostial occlusion. Mural trauma occurs when the tip or body of the catheter adversely affects the wall of the vessel. Specifically, the catheter tip should have memory and should further exhibit an elongated soft tip region to the vascular system and ostium.
C. The catheter tip should remain firmly engaged and present a stable platform in the ostium during introduction of the guide wire and/or angioplasty balloon catheter. That is, the tip and adjacent catheter body end region should provide mechanical backup and support for the other interventional and diagnostic equipment introduced into the lumen and projected from the catheter tip into the bodily organ.
D. The catheter should not become deeply engaged in the coronary artery during advancement or withdrawal of the angioplasty balloon catheter. In other words, the catheter should have a stable shaft and may include a braided wire to enhance mechanical support about the catheter body.
E. The internal lumen of the catheter body should remain lubricious to minimize friction during movement of the angioplasty balloon catheter therethrough. For example, the inner body of the catheter may be made of fluorinated polymer.
F. The catheter should allow adequate monitoring of the coronary ostial pressure and distal anatomy. In other words, the catheter should have an inner diameter retention.
G. The outer diameter of the catheter should present the smallest possible French size (circumferential diameter) to minimize trauma and bleeding at the insertion site. In other words, the catheter body should be as small as possible.